The disclosure relates generally to mobile communications systems and related networks, such as Universal Mobile Telecommunications Systems (UMTSs), its offspring Long Term Evolution (LTE) and 5th Generation New Radio (5G-NR) described and being developed by the Third Generation Partnership Project (3GPP), and more particularly to radio access networks (RANs) and user mobile communication devices connecting thereto, including small cell RANs, implemented in such mobile communications systems.
Operators of mobile systems, such as UMTS and its offspring including LTE and LTE-Advanced, are increasingly relying on wireless small cell RANs in order to deploy for example indoor voice and data services to enterprises and other customers. Such small cell RANs typically utilize multiple-access technologies capable of supporting communications with multiple users using radio frequency (RF) signals and sharing available system resources such as bandwidth and transmit power. Evolved universal terrestrial radio access (E-UTRA) is the radio interface of 3GPP's LTE upgrade path for UMTS mobile networks. In these systems, there are different frequencies where LTE (or E-UTRA) can be used, and in such systems, user mobile communications devices connect to a serving system, which is represented by a cell. In LTE, each cell is produced by a node called eNodeB (eNB).
A general principle in LTE or E-UTRA system is that a serving system (e.g., an eNB in such system) provides a measurement configuration to the mobile communications devices to “point” the receiver of the user mobile communications device to find other systems (e.g., neighbor cells) transmitting at a specified frequency(ies) (e.g., at 1900 MHz, 2522.375 MHz, etc) according to the measurement configuration that the user mobile communications device should measure. The measurement of communications signals of other systems by the user mobile communications device at specified frequencies is performed for variety of purposes, including inter frequency mobility and inter-frequency measurements. The user mobile communications devices can find these communications systems and perform actions, such as cell reselection in the idle mode and sending of measurement reports (e.g., Measurement Report Messages (MRMs)) in the active mode. These measurement reports can be used by the serving system to, for example, trigger handovers or to gather information about neighbor cells through Automatic Neighbor Relation (ANR) discovery. For example, a serving system of a mobile network operation (MNO) may use the MRMs for selecting handover targets for user mobile communications devices, to cause the user mobile communications devices to be serviced by a different cell for optimizing communications. Foridle mode user mobile communication devices, this measurement configuration information may be delivered in a System Information broadcast, which is used by the eNB to indicate, point out, and/or determine systems and frequencies in the pertinent area and in particular to indicate to the user mobile communications devices the appropriate measurement configuration parameters. For active mode user mobile communication devices, this measurementconfiguration information may be delivered in user mobile communications device-specific radio resource control (RRC) signaling messages, and in particular in RRC messages that indicate to the user mobile communications devices the appropriate measurement configuration parameters. In these measurement configuration parameters, there are specific instructions about what frequencies the user mobile communications device should measure. The information discovered by the user mobile communications devices buy performing such measurements may then be reported back to the serving system or used for initiating mobility functions.
As part inter frequency measurement process, the frequencies to which a serving system instructs a user mobile communications device to point to are indicated by the specific center frequency, or more particularly the E-UTRA Absolute Radio Frequency Channel Number (EARFCN). The EARFCN is an integer number that points to a specific carrier frequency of interest (e.g., 1825,375 GHz). Being that the EARFCN represents a specific center frequency, it is easy for a user mobile communications device to tune its receiver to that frequency and determine if there are any other communications systems transmitting on that frequency in the surrounding area of the user mobile communications device. In many situations a user mobile communications device is not performing measurements on any other frequencies than the specific EARFCNs provided to the user mobile communication device by the serving RAN. A MNO can easily configure its serving systems with the desired EARFCNs to communicate to a user mobile communications device as part of inter frequency measurement process, because MNO will know the exact frequency spectrum (i.e., bands) of other potential neighbor cells as they typically do belong to the same MNO in the mobile communications network of the serving system. Such frequency bands are typically licensed to that particular MNO, namely to the same MNO who is operating the serving system. The use of specific EARFCNs by each cell in the area is thus knows to the MNO and thus it is generally possible to precicly point the user mobile communication devices to all the specific EARFCNs in which it may find suitable or other cells able to provide service to the user mobile communication device. If “foreign” operations are detected within the MNO's licensed frequency band, the MNO can determine possible misuse of their licensed spectrum.
However, new mobile access systems exist that use spectrum that is independent of a MNO or is not under full control of the MNO in the same way as traditional licensed spectrum may be. Examples of such spectrums include unlicensed spectrum, shared spectrum, spectrum licensed from a third party, spectrum associated with citizens broadband radio service (CBRS), and so on. In these cases, spectrum allocation, or channel allocation, may be performed by a technique or procedures that occur independently or semi-independently of the MNO, such as by Spectrum Allocation System (SAS) for example. As an example, if a CBRS system is operated in a stadium or arena by a third party, the CBRS system may be dynamically assigned a channel, or operating spectrum, by a SAS. Due to this independent and dynamic nature of spectrum allocation, it would be very difficult for all surrounding MNO systems to be constantly aware of all the actual frequencies in which these third party systems were allocated and currently operate on. However, if the third party has a business agreement with a MNO, the third party CBRS network may however be configured to serve user mobile communications devices associated with a specific MNO or a specific set of MNOs. In so doing, the CBRS system is broadcasting the public land mobile network (PLMN) identifications (IDs) (PLMN IDs) of the associated MNOs to enable the user mobile communications device connection. Even with the business relationship between the MNO and the third party operation CBRS systems, the MNO may be completely unaware of the specific frequencies allocated by the SAS to the CBRS system for communications. Even if the third party was made aware of such frequency allocation, this allocation may change dynamically due to steps taken by the CBRS SAS s for frequency optimization or other purposes. For example, if a Navy vessel requires use of the spectrum for radar, frequencies available for a CBRS will be impacted and thus spectrum allocations may be dynamically shifted by a CBRS SAS. Thus, it is difficult and undesirable to have a requirement that each MNO needs to be up to date with a list of employed, allocated frequencies that the systems around them currently use. Requiring such updating would create undesired operational coupling between the third party communications systems and the MNO communications systems.
No admission is made that any reference cited herein constitutes prior art. Applicant expressly reserves the right to challenge the accuracy and pertinency of any cited documents.